1. Field of the Invention
The invention relates to combustion turbine combustor housings. More particularly, embodiments of the invention relate to paired combustor housings wherein a pair of adjoining combustors shares a common Siamesed housing wall, so as to reduce combustor circumferential spacing around the combustor midframe. Reduced combustor circumferential spacing facilitates adding one or more additional combustors within a given midframe circumference or reducing the frame circumference to accommodate the same number of combustors.
2. Description of the Prior Art
Referring to FIGS. 1-3 an exemplary known construction industrial combustion or gas turbine engine 10 is shown. The exemplary engine 10 includes a compressor section 12, a combustor section 14, a turbine section 16, and an exhaust section or system 18. The combustor section 14 includes a plurality of combustors 20 that are arrayed about a combustor midframe 22, within combustor housings 22A. Each combustor 20 is communication with the combustor section 14 interior via a corresponding combustor portal 23 formed in the combustor housing 22A. Each combustor 20 has a “top hat” cover 24 that is affixed to a combustor portal mating surface 26. The combustor portal mating surface 26 has an array of threaded apertures 27 about its circumference that are aligned coaxially with a top hat flange 28 and its array of corresponding through hole apertures 29. The top hat cover flange 28 is then affixed to combustor portal 23 by passing top hat cover fasteners 30 through the through hole apertures 29, which then engage the corresponding combustor portal mating surface threaded apertures 27.
As shown in FIG. 3, some exemplary known combustor housing configurations include a circumferential support web 32 that is formed between adjacent combustor housings 22A and their corresponding combustor portals 23. The series of known independent stand-alone combustor housings 22A and corresponding combustor portals require adjacent circumferential spacing S for lateral clearance between adjacent combustor cover top hat flanges 28. Thus, in any given engine design, the combustor casing 22 annular inner and outer diameter are largely determined by the number of combustors, their combustor portal 23 diameter and the lateral clearance S between adjoining combustor portals.
It is desirable to minimize combustion case annular inner and outer diameter so as to minimize the case required fabrication size, which can only be accomplished by reducing the number of combustors, the combustor portal diameter or lateral spacing between combustors. Conversely it is desirable to maximize the number of combustors in a turbine engine design.